/**
 * Copyright 2010-2011 initialize4j.org
 * 
 * <pre>
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * </pre>
 * 
 * <pre>
 * http://www.apache.org/licenses/LICENSE-2.0
 * </pre>
 * 
 * <pre>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 * </pre>
 */
package org.initialize4j.service;

import java.lang.reflect.Field;
import java.util.Arrays;
import java.util.Collection;

import org.initialize4j.annotations.WhenCondition;
import org.initialize4j.service.transform.AnnotationTransformer;

import com.google.common.base.Predicate;
import com.google.common.base.Predicates;
import com.google.common.collect.Collections2;

/**
 * A PreconditionInspector inspects that some mandatory precondition for
 * initializing is given.
 * 
 * @author <a href="hillger.t@gmail.com">hillger.t</a>
 */
final class InitializePreconditionInspector {

	/**
	 * Returns True if some defined precondition for an annotated field is
	 * satisfied.
	 * 
	 * @param value The value to inspect.
	 * @param field The field to inspect.
	 * @return True if the condition is satisfied - false otherwise.
	 * @throws InitializeException
	 */
	boolean isPreconditionSatified(Object value, Field field) {
		Collection<WhenCondition> conditions = Collections2.transform(Arrays.asList(field.getAnnotations()), new AnnotationTransformer());
		conditions = Collections2.filter(conditions, Predicates.notNull());

		for (WhenCondition when : conditions) {
			@SuppressWarnings("unchecked")
			Predicate<Object> satify = (Predicate<Object>) InitializationUtil.instance(when.value());
			return satify.apply(value);
		}
		return false;
	}
}
